Comparison Maiwo K3502-U3S vs Orico 3569S3-BK

The general purpose of the pocket.

Note that for different types of such accessories (see above), a different division is used according to purpose. So, external pockets are divided into portable and stationary, and internal pockets are divided into laptop models, PC chassis and server solutions. For docking stations and cases, this parameter is not specified at all: the former initially assume stationary use, the latter, again, are portable by definition.

Here is a more detailed description of the options relevant for external pockets:

— Portable. Models designed for frequent moving from place to place and even for use on the go (for example, connecting to a laptop on the road). Most modern external pockets fall into this category — after all, initially external drives (which such pockets are an alternative to) are also made predominantly portable. The specific features of these accessories may vary, but they are all quite compact and designed for only one internal drive, and they receive energy from the same USB port they are connected to (see "Power").

— Stationary. External pockets designed to stay in one place all the time and do not involve frequent movement and use on the road. Such models are much less common than portable ones; most of them are rather l...arge designs, designed to install 2 or more drives, and are often a kind of "NAS-server without networking". However, there are also models for 1 slot — they usually differ from portable counterparts in the presence of a stand that allows you to put the pocket vertically (so that it takes up less space on the table), and is powered by a power supply unit.

In turn, internal pockets for different purposes have the following specifics:

— For laptops. This type is usually designed to install 2.5" or M.2 form factor drives in the optical drive bay (CD / DVD) — due to the compact size of laptops, this is often the only possible way to install an additional drive.

— Chassis. Pockets designed for regular desktop PCs. Note that the term "chassis" traditionally refers to only one special kind of such pockets — the so-called Mobile Rack, colloquially known as "sled". The main function of such accessories is to provide the ability to quickly move drives from one case to another. To do this, the design provides for two parts: a base, which is mounted in a 5.25" slot on the case, and a removable cartridge, into which the drive is installed directly. To prevent theft or unauthorized physical access, the "sled" can be equipped with a lock that blocks the removal of the drive. Our time is used quite rarely, mainly when working with disk arrays, as well as in some other specific cases — for example, so that after the end of the working day you can take a disk with materials with you or hide it in a safe to ensure confidentiality.
Another kind of PC pockets are adapters for installing drives in non-standard seats. The classic case is the use of a 2.5" laptop drive in a 3.5" desktop case, but nowadays there is a more specific option — the use of an SSD M.2 drive as a PCI-E expansion card (for more details, see "Form factor") .

— For the server. Server systems most often have to deal with large volumes of information that require high reliability and/or speed of access. Thus, most pockets of this purpose are designed for several drives (from two to six) — this allows you to provide the necessary volumes and, if necessary, organize a RAID array of one or another level. At the same time, built-in support for RAID (see below) is not found in such devices — it is easier and more reasonable to organize it using the server itself. It is also worth noting that according to the method of installing disks, such pockets usually refer to “sleds” (see “Chassis” above) — this provides additional convenience, allowing, for example, quickly replacing a failed drive in a RAID array. Server pockets can use specialized connection interfaces like SAS, although traditional SATA is still more popular.

The form factor of the drive that the pocket is designed to hold.

Such accessories are made for standard form factors of internal drives: 3.5 ", 2.5"(often — for both at once), as well as M.2 SSD. Here are the features of each of these options:

— HDD 3.5 ". 3.5" is the traditional form factor of internal drives for full-size desktop PCs. Accordingly, internal pockets for this form factor are used exclusively in PCs or servers, they are too bulky for laptops; moreover, most of these pockets are a chassis — "sled" (see "Purpose"). External solutions turn out to be more bulky than models under 2.5", however, due to the absence of strict restrictions on the size, capacious drives for such pockets are much cheaper than miniature analogues of the same capacity. Also note that most 3.5-inch drives are just traditional hard drives (or hybrid SSHD devices), SSD modules in this form factor are practically not produced.

SSD or HDD 2.5". Therefore, the internal pockets of this form factor are intended primarily for laptops; a classic version of such an accessory is an adapter for installing a drive in an optical drive slot. In PC models, this option has not received much distribution — modern desktops usually have not only 3.5-inch, but also 2.5-inch drive bays; and for a number of reasons, it is more convenient to use 3.5" solutions as quick-release "...sleds" (see above). But for servers, internal pockets of this form factor are available — for several slots; they usually also represent a "sled" chassis. What As for external models, 2.5" pockets are noticeably smaller than 3.5" counterparts, however, drives for them are more expensive per gigabyte of capacity (especially with large volumes).

— SSD or HDD 2.5"/3.5". Models designed for two form factors at once. The meaning of this marking depends on the particular type of pocket. So, in external models and docking stations (see "Type"), it usually means the ability to install a drive of any of the two form factors in your pocket, to choose from. Usually, bays or slots in such models are initially designed for 3.5", and special plugs are used to fix 2.5" drives in such slots (note that there may be fewer such plugs in docks than sockets). A similar design is used in internal models for servers, as well as in PC chassis that look like a "sled" (see "Intended use"). However, in PC models there is another option — adapters for accommodating 2.5" HDD / SSD in 3.5" form factor slots ; such accessories are also included in this category.

— SSD M.2. Form factor designed specifically for miniature internal components, including solid state drives. Dimensions of M.2 peripherals are from 12 to 30 mm wide and from 16 to 110 mm in length, such components are connected through the connector of the same name. External pockets of this form factor are compact in size. In turn, internal models are most often laptop solutions for installing an SSD in an optical drive slot. However, there is also a rather specific option — PC accessories that allow you to connect M.2 drives to a PCI-E slot (like a separate sound card or another expansion card).
Note that the connection via M.2 can be carried out both on the basis of PCI-E and on the basis of SATA; for more details, see "Drive interface", here we note that the current moment and compatibility with a specific drive should be specified separately.

The number of separate slots for drives provided in the design of the pocket, in other words, the number of drives for which this model is designed.

In addition to models for one slot, nowadays you can find more capacious solutions — for two drives, or even more. Such "multiplying" is found in three types of devices. The first is large-format pockets for stationary purposes (see above), operating in the format of separate storages for a large amount of data. Such models may support RAID arrays (see above) and other special features. The second type of devices with more than one slot are separate docking stations (see "Type") with similar functionality. The third type is server models (see "Purpose") with an internal installation; they again allow the organization of arrays, but by means of the server itself.

Note that external devices with one slot can be powered from the USB port, but several drives in this case inevitably require a separate PSU (see "Power").

The maximum storage capacity supported by the pocket. In models with multiple disks/SSDs (see "Drive Slots"), this item indicates the largest total volume supported by the device; by dividing this capacity by the number of slots, you can determine the maximum allowable capacity of each individual drive.

The limitation on the maximum volume is relevant mainly for external models, including docking stations (see "Type"). This is due to the fact that fundamentally different interfaces are used for the drive and for connecting the pocket itself in such models (most often SATA and USB, respectively, see above for details). For the normal interaction of such interfaces, an electronic controller is required; and the larger the volume of the installed drive (s) — the higher the requirements for the performance of such a controller.

Note that, other things being equal, supporting large volumes is more expensive, and capacious drives themselves are not cheap. Therefore, when choosing according to this indicator, it is worth considering real needs, and not chasing the maximum numbers.